elpa-seq binary package in Ubuntu Focal amd64

 This library provides sequence-manipulation functions that complement
 basic functions provided by subr.el.
 .
 All functions are prefixed with "seq-".
 .
 All provided functions work on lists, strings and vectors.
 .
 Functions taking a predicate or iterating over a sequence using a
 function as argument take the function as their first argument and
 the sequence as their second argument. All other functions take
 the sequence as their first argument.

Source package